The present exemplary embodiment relates to the lighting arts. It finds particular application in conjunction with light emitting packages based on one or more light emitting chips and to methods for making the same, and will be described with particular reference thereto. However, it is to be appreciated that the present exemplary embodiment is also amenable to other like applications.
Light emitting packages based on semiconductor light emitting chips, such as light emitting diodes (LEDs) are increasingly used for illumination purposes. LEDs consist of semiconducting material doped with impurities to create a p-n junction, wherein current flows from the p-side (anode) to the n-side (cathode). Each LED typically produces radiation that is saturated light at a single color point, such as red light, blue light, green light, violet light, or ultraviolet light over a narrow spectral range. It is known to operatively couple the LED with a wavelength converting phosphor so as to produce a desired light output such as an approximate white light output. It is further known to couple the chip with a transparent lens, which may be a molded encapsulant shaped into a desired lensing configuration, such as a dome.
Referring now to FIG. 1, a prior art LED lamp is disclosed (U.S. Pat. No. 7,029,935), comprised of a mounting substrate 10 which receives a light emitting diode 12. The LED 12 is disposed within an encapsulant 14. A transparent plastic shell 16 includes a phosphor 18. A transparent inner core 19 tills shell 16. In alternative devices, the phosphor is coated directly on the semiconductor light emitting device itself. Alternatively, the phosphor is coated directly on the surface of the shell.
Application No. 2008/0054280, incorporated by reference herein, discloses a light emitting package with a light emitting chip supported by a circuit board. A light transmissive shell is disposed over the light emitting chip in a dome-like shape. A phosphor slurry is spray coated onto the inner surface of the shell, which is then cured. This method provides acceptable color variation; however, this method results in a large amount of phosphor waste due to imprecise control over the coating method.
The present embodiment provides a light emitting package having improved properties and desirable benefits.